i found mine here http://www.cakestuff.co.nz and i'm sure you can buy it at your local cake decorating supplier shop.
after i got mine, i've doodled on some of my cookies:
i've covered my cookies with white fondant and leave it to set overnight so i'll have a hard surface to doodle on. it was a lot of fun!
if you are interested, click on the bottom image link to go & get it....